Development of a low debris x-ray backlighter source via laser irradiation of a cluster gas medium

X-ray backlighter sources, typically based on laser irradiated solid targets, are of great importance for radiography of transient plasmas produced in high power laser-target interactions. Here we report on the development of an atomic cluster gas based x-ray source and assess its viability for x-ray point projection imaging motivated by the debris free, high repetition rate nature of laser-cluster gas interactions. The dependence on cluster size and atomic number of the anisotropic radial x-ray distribution, 100$\mu $m x-ray source size and multi-keV free electron temperatures produced by the interaction of a 1TW short pulse (500fs), high contrast laser system operating at 1054nm with high density Ar, Kr and Xe cluster gas media have been investigated. Previously, when propagated through a large (10mm) volume cluster gas medium at 10\textasciicircum 17 atoms/cc, \textgreater 95{\%} of the laser energy contained in a short pulse was absorbed launching a strong, radiative cylindrical blast wave. At 10\textasciicircum 19 atoms/cc, the absorption of the laser energy by the cluster gas medium was high (\textgreater 85{\%}). However, optical probing at 2$\omega $ showed that the laser energy was predominantly absorbed at the edge of the gas volume where the energy absorbed per unit length rapidly changed over a scale length of 2mm launching a radiative, elliptical blast wave.